Balanced valve



Nov. 2, 192e. 1,605,379

F. WAGNER l l BALANCED VALVE Filed Sept. 6,

/ zi ja/ Nj `1:2:v `=1=2sl 13 2 Inventor: fr r l" 1 l Patented Nov. 2,1926.

UNITED- STATES PATENT OFFICE.' i

BALANGED VALVE.

Application f led September 6, 1924, Serial No. 73,239, and in Germany December 31, 1923.

hammering of the main valve and the auxiliary valve is prevented without resorting to the inconvenient expedient of providing a balancing' piston.

To this end, I provide a second throttle in connection with the main valve by which throttle the admission of live steam to the area laid open by the main valve, when 1t 1s lifted from its seat, is so restricted that the impetus which the steam imparts to the mainvalve in lifting it, becomes zero after the main valve has performed a comparatively short stroke.

. In a preferred embodiment of myinvention, this secondvthrottle comprises a restricted passage between the wall of a cylinder in the valve housing and the main valve,

' through which passage the live steam tlows to the seat of the main valve.

By the cooperation of these two throttles, hammering is effectively prevented and a balancing piston is eliminated.

Hammering in valves of the usual type is due to the fact that the admission of live steaml to the seat of the main' valve is unrestricted, so that the pressure it exerts on the main valve is practically equal to its initial pressure, and the main valve, which, at the time of lifting is practically relieved from pressure, strikes the auxiliary valve with a heavy blow. VWhen the auxiliary valve is closed, steam is trapped in the counter-pressure chamber, and live steam flows to said chamber through the clearance between the main valve `and the valve casing, and pressure builds pp gradually insaid chamber and finally vorces the main valve away from'the auxiliary valve. This relieves the pressure in the `counter-pressure chamber and the live steamv pressure on the 4 lower face 'of the main valve again throws it against the auxiliary valve sothat there is permanent hammering of the valves.

To overcome the tendency to hammer, it has beenl proposed to combine the said first throttle with a balancing piston at the main valve which causes compression in the coun? ter-pressure chamber in conformity with the motion of the main valve. This expedient prevents hammering, but, as mentioned, is

not satisfactory as the diameter of the ybalancing piston is inconveniently large, and' so the valve becomes correspondingly large, heavy, and expensive.

. In my invent-ion, hammering is, prevented.

Without this objectionable expedient.

in the accompanying drawing two illustrative forms. In these drawings:

Figs. 1 and 2 are vertical sections through twosteam valves,and

Fig. 3 is a plan of the main valve used in either form. V

In the construction illustrated, the valve casing or cylinder 1 has a cover 2, and encloses the main valve 3 one end of which lforms a piston adapted to having a sliding' it in said cylinder. An auxiliary valve 4 is mounted in the main valve, and a counter'- pressure chamber 5 is formed between the main valve and the cover. In the main valve, 3 is disposed an annular member 6 through which projects the valve stem or shank 7, which is connected at its lower end with the auxiliary valvel 4. This annular tted about the valve shank 7. At the top,

the chamber 9 is in communication with the counter-pressure chamber 5 by means of an annular passage I1l about the valve shank.

To elucidate the invention I have showlA Two tubes 12 connect the chamber 9 with 'i the live steam` chamber 13 of the valve. In `both forms the valve shank 7 is provided with an annular member for controlling the passage 11. In Fig. 1 this annular member or ring 14 projects downward through the 'bottom plate 10, and its diameter is slightly smaller than the diameter of the opening 11. In Fig. 2, the ring li upon the shank 7 is disposed within the chamberA 9, and its diameter is larger than the diameter of opening 11. Below the main valve is a chamber 15 to which the I,steam header (not shown) is connected.

The drawings show the valve in closed .condition in which there is present in the counter-pressure Vchamber 5, the same steam pressure s inthe -llve steam chamber 13 of the valve, since these two chambers are 1n communication with each other through the tubes 12 and the annular passage 11. This connection between the two chambers remains open even after opening of the auxiliary valve 4. The diameter of the auxiliary valve is such that the engine or engines, the

pipe lines of which are connected to thel from the chamber 13 to the counter-pressure chamber 5. By the throttling of the supply of live steam to the counter-pressure chamber 5, there will be caused immediately a rapid equalization of pressure between the counter-pressure chamber 5` and the chamber 15 of the valve. The main valve which is thus balanced will be moved upward from its closed position by the further opening stroke of the valve shank by the upper surface of the auxiliary valve 4 coming into contact with the lower surface of the plate 10 immediately after throttling the live-steam supply in passage 11. v

If the stem 7 is moved no further after the main valve 3 has been lifted from its seat, the following action takes place. As soon as the main valve 3 opens, live steam from the chamber 13 flows to the chamber 15 through the narrow clearance between the skirt of the main valve and the cylinder 16. The steam is intensely throttled in this clearance, but yet will be under a certain excess pressure when arriving below the main valve so that it is able to impel the main valve upwards with a certain acceleration, but its excess pressure becomes zero as soon as the width'of the gap between the main valve and its seat exceeds the clearance between its skirt and the cylinder 16, and so no further upwardly directed pressure will be exerted on the main valve.

In fact, the upward motion of the main valve is terminated even at an earlier period because when the main valve is raised it moves clear from the top of the auxiliary valve 4 and, at the same time, the ring 14 permits live steam to 'ow to the counter pressure chamber 5 through the -annular gap 11, and this live steam now exerts pressure on the upper face of the main valve 3 so that the main valve is not only arrested but is reversed until' it has resumed its normal posit-ion on the auxiliary valve 4. This is effected without hammering as the live steam passage through the annular clearance 11 is throttledand finally closed by the ring 14 and so the pressure on the upper face of the main valve is reduced to zero.

The area which the valve 3 lays open when it is lifted from its seat, is always considerably in excess of that of the clearance through which live steam is admitted to the main valve past its skirt and the cylinder 16 and so the quantity of steam which actually flows through the main valve is considerably belowy the quantity which might flow through the chamber 15.

' This condition is the same for any opening of the main valve and so no sudden surges of pressure will act on the main valve.

The only condition under which the main valve might be lifted from its normal position on the top of the auxiliary .valve is iiuctuating steam consumption, for instance, in a reciprocating engine where surges of unusual magnitude occur. Such surges, however, will form only gradually and so the main valve will be set in motion gradually as well and will be returned immediately by the supply of live steam tothe counterpressure chamber which is eected as described.

For completely eliminating all oscillations of the main valve, the ring 14a in Fig. 2 is shown so disposed upon the valve shank that it is located entirely within the chamber 9 and the bottom area of the chamber exceeds the cover area by the area of the annular passage 11. Also, the diameter of the rlng 14 in this embodiment is greater than the diameter of the annular passage 11. The steam escaping from the counter-pressure chamber after the opening of the auxiliary valve 4, will be replaced by steam supply from the live steam chamber 13 until the annular opening 11 is cloed by ring 14a,

which now acts simultaneously as a shoulder for opening of the relieved main valve. Ihe opening of the main valve is effected without impact, since its lower part 1s guided 1n the cylinder 16 as in the case of the valve of Fig. 1. Since the bottom area of the chamber 9 is greater than its cover area, the excess pressure generated in the chamber during relieving of the main valve, exerts a downwardly directed pressure upon the main. valve. Accordingly, as soon as .the main valve leaves its closed position, it is pressed downward upon the ring 14a through excess pressure. At the same time, however, it is soiconnected' with the valve shank that it must follow each one of the motions of the latter as if the connection were a mel v weight.

When the stem 7 is moved downwards, the main valve 3 will. follow under its own If it should lag by accident, the supply. of, live steam to the counter-pressure chamber 5 which would be set up Immediately, would cause the main valve to return to its initial position immediately. ,When lifting the main valve from its seat, considerable resistance due to'adhesion must be overcome, particularly in large valves. To overcome this resistance I preferably provide' the main valve 3 with a diii'erential balanc-- ing piston 17 as indicated in Fig. 2. Its diameter is only a few mm. larger than the smallest diameter of the main valve.

TWhen, in a valve of this type, the ring 14a restricts the passage 11 to suchan extent that less steam flows to the counter-pressure chamber 5y than is discharged from said chamber through the'auxiliary valve 4, the live steam in the chamber 13 exerts excess pressure on the dierential piston 17 which pressure increases as the pressure in the chamber 5 decreases and causes the main valve 3 to open automatically before the passage 11 has been completely closed. This lifting motion of the main valve, however, is immediately arrested by the combined action of the throttle 14, or 14", and the clearance in the cylinder 16, and the main valve is reversed but its motion is arrested when vthe passage 11 has been so restricted. that only as much live steam enters 'the counter-pressure chamber 5 as4 is discharged from it through the auxiliary valve 4. The main valve is nowpermanently held in its intermediate or ioating position as all forces acting -on the main valve are completely bal-- anced.

' T he conditions of equilibrium of the main valve l are disturbed by any further displacement of the stem 7 as the' ring 14a, on upward motion of the stem, increases the throttling action on the live steam, and, on

downward motion,` decreases it. Under the action of the variations of pressure brought about in the counter-pressure chamber ,5 the Vmain valve follows the valve stem immediately and until it has assumed its new position of equilibrium.

In the construction illustrated ink Fig. 1,

' the flow of the live steam to vthe counterpressure chamber 5 is regulated by the throttlc 14, its upper surface cooperating with its only possibilities, nory do I desire to be limited to the lspecic construction of the second throttle, viz, the cylinder 16 with its Earow clearance, as this also may be modi- Having thus described my invention, what. I claim as new and desire to secure by Letters Patent is 1. In a valve, the combination of a valve box having an inlet and an outlet, a main valve body made in an outer and an inner section, the inner section formed with a chamber having a removable bottom and communicating with said inlet, said valve box being formed with a chamber arranged so that pressure fluid confined therein tends to force the main valve body on its seat and communicating with said chamber of said inner section, an auxiliary valve body controlling the discharge from said chamber of the valve box, and means for operating said valve bodies comprising a stem ,passing through a bore of said removable bottom.l

2. In a valve, the combination of a valve box having an inlet and an outlet, a mainvalve body made in an outer and an inner section, the inner section formed witha chamber communicating with said inlet, said valve box being formed with a chamber arranged so thatpressure fluid confined therein tends to force the main valve body on its seat and communicating'with said chamber of said inner section through a central opening made in the wall of said inner section, an auxiliary valve body controlling vthe discharge from said chamber of the valve box,

and. a valve stem connected with said auxil- Y sage being smaller than the area of the wall of the chamber located opposite to the annular passage.

3. In a valve, the combination of a valve box having an inlet and an outlet, a main valve body made in an outer and an inner lsection, the inner section formed with a chamber communicating with said inlet, said valve box being formed with a chamber arranged so that pressure fluid conined therein tends to force the main valve body on its seat and communicating with said chamber `of said inner section through a central opening made in the wall of said inner section, an auxiliary valve body controlling the d1scharge from said chamber offthe valve box,

and a valve stem connected' with said auxi-l' iary valve and passing through the chamber of said inner section? and said central openmg and providing an annular passage with the wall of the opening through which the chamber of the inner section communicates with said chamber of the box, said valve stem carrying a collar in position for controlling 'said annular passage and having a diameter larger than the outer diameter of said annular passage, the area of the Wall of the chamber Surrounding said annular passage being so much smaller than the area of the wall of the chamber located opposite tq the annular passage that when the main valve body is removed from its seat the differential iuid pressure acting on said walls is sufficient to hold the main valve body on said collar.

4. In a valve, the combination of a valve casing having an inlet and an outlet, a main valve therein for controlling said outlet and cooperating with said casing to 1to1-m a counter-pressure chamber, and said valve having a chamber therein in open communication With said casing inlet, and a passage connecting said chambers, and said main valve also having an outlet trom said counter-pressure chamber to .the outlet of the main casing, an auxiliary valve for controlling said main valve outlet, a valve stem for said auxiliary valve, and a throttling member on said stem in said second mentioned chamber, and of smaller diameter operating with the end wall of said second mentioned chamber to restrictcommunication through said passage upon opening the auxiliary valve, and serving to close said passage and engage with said main valve to open the latter upon further movement of the auxiliary valve.v

5. A balanced valve comprising a cylinder having an annular seat at one end, an outlet beyond said seat and an inlet in the peripheral wall, and spaced from said seat, a main valve defining an interstice between itself and said cylinder intermediate said seat and said inlet, a piston part having a sliding fit in said cylinder at the opposite side ot' said inlet, said piston part having a passage therethrough cstablishing communication between said inlet and said cylinder at the end thereof opposite to said seat, an auxiliary valve seating in said main valve and controlling communication between said last mentioned cylinder end and said outlet, and means connected with said auxiliary valve for restricting the area of said passage in accordance with the relative displacement of said main and auxiliary valves.

Signed at Berlin in the county of Brandenburg and State of Prussia, this 12th day of August A. D. 1924.

FRITZ W'AGNER. 

